In transitioning from warfarin or Coumadin® to rivaroxaban or brand name Xarelto®, it is important to know how it works: it stops clotting factor Xa from working, thinning the blood. It starts working after a few hours of taking it. If you stop taking it, your blood returns to normal clotting in 1-2 days.

For general information, these other tablets are also anticoagulants: apixaban, dabigatran, and edoxaban. Alcohol binge drinking in large amounts can increase rivaroxaban’s bleeding effects. Before getting a vaccination, show your anticoagulant card to your health professional. The best news is that while on this drug, there are no foods or drinks to avoid.

Laboratory Tests to do Before Switching

If you have Factor V Leiden deficiency, the first three blood tests ensure you do not have additional clotting deficiencies, and the 4th is to obtain your baseline kidney function, in case it changes on rivaroxaban:

Protein C

Protein S

Prothrombin gene mutation

Creatinine clearance

Blood Type – I would like to know your blood type, to determine if it is rare or common

Steps to Switching from Warfarin to Rivaroxaban

After baseline labs are done, then the next steps are to:

Discontinue warfarin

Wait until your international normalized ratio or INR is less than 3.0. There is one study showing an increased risk of bleeding in the first 7 days transitioning from warfarin to rivaroxaban (1.54% vs 0.2% for rivaroxaban vs. warfarin), which appears to be a rather small effect.

Then start taking rivaroxaban 20 mg/day

Key Notes on Rivaroxaban

Take after a meal or snack, to increase absorption

The most common side effect is bleeding easier, such as nosebleeds, bruising. This effect wears off in the first few weeks

Do not take together with St. John’s wort

If you ever have difficulty swallowing pills, it is okay to crush and then mix it with apple sauce or water, swallow, and eat a meal afterwards

You should carry an anticoagulant alert card all the time, to show for a medical or dental treatment

Signs of Bleeding

Of course, if you experience serious bleeding, stop taking rivaroxaban and contact your doctor, and go to the nearest hospital ER. Some signs to look for include:

Severe headache

Having red stool, urine, vomit or cough

New bruises for no apparent reason, or ones that keep growing in size

Nosebleed over 10 minutes

Most Common Side Effects of Rivaroxaban

These affect about 1 in 100 patients:

Fatigue, lack of energy

Shortness of breath

Noticeable heartbeats that are fast (palpitations) and pale skin – signs of anemia or blood loss

Feeling dizzy or lightheaded, especially when standing up too fast. You may need to get up slowly or sit back down for a short time before getting up again

Serious Allergic Reaction

Rarely, a serious allergic reaction requires the ER: red, swollen skin, peeling skin; wheezing; chest or throat tightness; trouble breathing or talking; swelling of lips, tongue, face, mouth, or throat. These are a medical emergency and you would call 911.

Drugs to avoid include the antibiotics erythromycin or clarithromycin, non-steroidal inflammatory drugs (NSAIDS) like ibuprofen and aspirin.

I hope this helps you to understand this new medication, and that you will soon be primed to enjoy eating and drinking anything you’d like.

Switching from Rivaroxaban to Warfarin

If you ever need to switch back from rivaroxaban to warfarin, it is associated with an increased clotting risk and there is not a lot of data on how exactly to do it. For good measure, spinal and epidural anesthesia are contraindicated in you, due to an increased risk for epidural or spinal bleeding that can lead to paralysis. If you ever go into kidney failure, we would take you off this drug.

Drugs to Avoid

We will also avoid the following drugs that can either accelerate or slow rivaroxaban’s effects:

CYP3A inhibitors that increase rivaroxaban’s effects:

Amiodarone for atrial fibrillation

Clarithromycin, erythromycin, or troleandomycin antibiotics used for bronchitis